Sound system and apparatus therefor



Oct. 10, 1939. B ZETKA 2,175,678

SOUND SYSTEM AND APPARATUS THEREFOR Filed Jan. 51, 1935 Flyz. F 74." F196: 60 6! 6'3 66 AA I/Q AMP. yrl

I la 67 VOLUME CONTROL 0 62 INVENTOR JOSEPH B. ZETKA BYWMMW ATTORNEY Patented Oct. 10,1939

UNITED STATES PATENT OFFICE" SOUND SYSTEM AND APPARATUS THEREFOR Delaware Application January 31, 1935, Serial No. 4,317

Claim.

and those using film in the manner of photogs raphy, are well known. In the latter method of sound recording, commonly called sound-on film, a source of light is a necessary element intermediate the sound source and the film for affecting the film in accordance with the variations in the sound source. This light source is perhaps the most vital element in the entire system, since it must faithfully translate electrical variations into light variations without changing its characteristics from time to time. This invention is particularly directed to this vital elem ment, and to the recording system in which it is employed.

An object of this invention is to record sound upon film in a simple, direct and efficient manner. Another object of this invention is to provide a recording lamp of low wattage, no inertia, longevity, sensitiveness, and one having a large working output.

A further object of this invention is to record sound using solely the recording lamp, that is,

the lamp provides the intermediate and associate optical apparatus now employed between the present type of lamps and film.

Referring to the present day systems above mentioned, there is placed in operable association with a lamp or light source a slit with its necessary flexible holder and mountings for the proper guidance of the film adjacent to the slit. Optical systems employing lenses and reflectors are also used for concentrating the light and directing it along definite paths. Lamps used with this apparatus have employed hot filament elements, which, through the natural process of evaporation and oxidation, cause deleterious effects with resulting extraneous noises commonly known as ground noise", it being understood, of course, that there are other sources of ground noise. There are other obvious defects in this type of recording lamp such as short life and sluggishness.

The lamp or light source of this invention, therefore, is one of the gas filled type, operating substantially cold, thereby preventing vaporization of the elements, decreasing blackening of the bulb, lengthening the life of the lamp, and providing a light source having substantially no inertia. Such lamps have been used heretofore, but not with the novel features of this invention, as will be described hereinafter. Perhaps the outstanding feature of the present lamp and system using it is the ability to pass to the film sub- 6 stantially all of the actinic rays produced in the gas glow. Another feature is the concentration of the rays produced to the necessary slit dimensions, eliminating much diffusion and absorption losses, and increasing the efllciency of 10 the lamp.

Other features and advantages of this recording lamp and system will be apparent from a detailed description thereof, and the invention will be more fully understood by reading the follow 15 ing description in conjunction with the accompanying drawing, in which:

Figs. 1 and 2, respectively, are plan and elevational views of a completed lamp,

Figs. 3, 4, 5 and Gare plan and cross sectional 20 views of the internal constructions of two modifications of the lamp of Figs. 1 and 2, and,

Fig. '7 is a diagrammatic sketch of a system and circuit employing the recording lamp of Figs.

1 and 2. 26

Referring specifically to Fig. 1, an envelope 5 of approximately one inch in diameter is mounted in a base 6 from which two terminals 1 and 8 extend for making connections between the internal electrodes and an external circuit. The

envelope 5 is preferably of Pyrex glass to which is sealed through various grades Ill thereof, which are indicated by the dotted lines, but between which no lines are actually present, a quartz cap H, which is shaped at the tip I2 either round, 36 approximately round or in quadrants, as shown in Fig. 1. This tip is proportioned and ground to act as a concentrating lens having a depth of approximately one-quarter inch at its thickest point, and is provided at the tip thereof with a 40 slit l3 having dimensions of approximately onetenth of an inch by .0008 inch, these dimensions depending upon the size of the film. The focus of the lens is a few thousandths of an inch ahead of the slit. The quartz element H, with the ex- 45 ception of the slit I3, may be painted black, or otherwise shielded from light filtration with any desirable material, such as black china marking ink, silver or the like. It is to be understood that various types of material may be used to make 50 the seal between the envelope 5 and the quartz I I, but one method, which I have found satisfactory, is the use of Pyrex graduated in temperature coefficients. Shown internally of the envelope 5 is a stem I5, in which two conductors l6 and I1 55 are connected to the electrodes and extensions 1 and 8.

Referring now to Figs. 3 and 4, the stem II is shown extending into a narrow portion 24, which flares out into a cupped portion 2|, which has been fused around a tungsten disc 22, this disc being connected to a tungsten lead-in conductor 23, the lower portion of which is surrounded with spaghetti 24 or other insulating material. The stem I5 is of Nonex suitable for a tungsten seal. The disc 22 is approximately one-sixteenth inch in thickness and five-sixteenth inch in diameter, and, when originally placed in the portion 2|, has a bright metallic luster. The surface of the disc and sides of the portion 2| are ground flush. This disc 22 forms one electrode and the cathode or target of the lamp.

Mounted above the cathode a distance of approximately .0l7 of an inch is an anode 24 formed of a ring of Swedish iron approximately .005 inch in thickness. This ring 24 has a surrounding nickel ring 25 to stiffen it, the rim and ring 24 being supported on a wire 26 welded at 21 to a tungsten lead-in conductor 28, passing through an extension 29 of the stem l5. There is thus formed the two electrodes, namely, the cathode 22, which is the target of the lamp, and the anode 24 between which a glow is produced in gases such as nitrogen, helium, neon or argon or combinations thereof. Although I prefer nitrogen at appoximately 13 111/111 pressure, other gases, such as helium-argon at 8 m/m of pressure, or argon-neon at 4 m/m, may be used. It is to be understood, however, that this invention is not limimd to any particular gas,or pressure. It is to be noted that in the formation of this lamp, the cathode and anode are sumciently heated to a point where they have a slight discoloration, such as steel blue, this treatment having been found to decrease ground noises. It has been found that, if the electrodes remain in their original metallic state, or are oxidized to a. considerable degree, recording is not as satisfactory as when treated to the steel blue color.

It is to be understood that other types of glass may be used for the stem and envelope portions of the lamp, such as Corex and the like, or lead glass, but I prefer the use of Nonex in conjunction with the tungsten lead-in wires and various grades of Pyrex for the body portion of the lamp envelope and for making the quartz to glass seal. Furthermore, other methods of supporting the anode adjacent the target or other configurations of the electrodes may be used without departing from the spirit of the invention, but I prefer the modifications disclosed herein.

Referring now to Figs. 5 and 6, a double support construction is shown, having a rectangu lar or slit like shape. Upon a stem are three extensions 36, 31 and 38, the extension 36 being iormed into a cup portion 40, to which is fused a tungsten target 4| rectangular in shape, the surface of the target being ground fiush with the top of the portion 40 as in Fig. 4. A tungsten lead-in conductor 42 connects the target or cathode 4| with the external elernent, the lower portion of which is insulated with spaghetti insulation 44 or like material. The extensions 31 and 38 have mounted therein tungsten lead-in wires 41 and 48 to which are welded, at points 50 and 5!, a Swedish iron ring anode 53 rectangular in shape to conform with the cathode through extensions 54. The purpose of the two extensions 54 is solely for supporting the anode 53, it being understood that the anode may be mounted similarly to the construction in Pig. 4. The process of treatment of the cathode 4| .and anode II is similar to that of the modification in Figs.

3 and 4, and the connections therefor are similar, the two leads 4! and 44 being connected together to form a single connection through the mounting 6 of Fig. 2.

With the above described construction, it is possible to bring the actual source of light production, which is between the anode and cathode, and which is evenly distributed over the cathode or target, extremely close to the tip of the lamp and, consequently, the film to be affected. Now by the use of a quartz lens, the quartz passing practically ninety per cent of the usable light rays produced and substantially all of the actinic rays, the rays being concentrated through the lens action of the quartz as formed, there is obtained a highly efficient light source. Combining this construction with the slit formed at the extreme tip of the quartz, there is presented within a few thousandths of an inch, directly adjacent the slit, a concentration of light not possible with any other system heretofore known. Since the source of light is a gas and a large proportion of the generated light available for use, the lamp is especially eflicient in the recording of high frequencies. As mentioned above, the quartz tip is so formed and the slit so placed that the rays are brought to a focus within a few thousandths of an inch from the slit, and at the point at which the film is passed. With such a lamp, exhausted to a pressure in the neighborhood of 13 m/m when nitrogen is used, the current requirements are between 5 and 10 milliamperes to provide an affect upon the film comparable to lamps now using 20 to 40 milliamperes. It is thus possible, with the use of such a lamp, to use dry batteries instead of the large current capacity storage batteries, which are inconvenient for portable use. Another advantage of a lamp requiring such a low current capacity is that the life of the tube is greatly lengthened.

Referring now to the diagrammatic circuit in Fig. 7, a translating device 60, in the form of a microphone, is connected to an amplifier iii, the amplification of which may be controlled by a volume control 62. The amplifier 6| may be supplemented by another amplifier 63, the output of which is fed into a lamp 64 of the above description. To illustrate the simple apparatus necessary for recording with such a lamp, the lamp is shown, together with a film 6B, in operable relation thereto. The film runs in a guide block 61, the film being taken from a reel 68 and taken up by a reel 69, or vice versa. The film runs a few thousandths of an inch ahead of the slit of the tube, thus eliminating an optical system and slit holder. It is well known that these last mentioned elements not only cause light losses but are a source of considerable trouble, as the slit holder pressure is never unlform, and there is always a tendency to scrape and tear the film. There are also large light losses, due to transmission and diffusion, as the film must be placed a considerable distance rom the light source. The old systems require more careful attention to keep all elements in adjustment and clean during a film run, while with the present invention there may be provided ample room to dispose of dust and dirt, which adheres to new film and which has a tendency to collect in the present type of slits. Furthermore, unevenness of the film is not a hindrance,

since plenty of space may be provided, while maintaining one surface of the film the proper distance from the lamp.

The above description has been directed to a quartz tip lamp, but it is to be understood that I have made lamps having the above features of construction such as the lens with the included slit, wherein I used tip portions of Corex, Pyrex and like material, these lamps, of course, not passing the quantity of actinic rays that are transmitted by quartz. Furthermore, the tip portions may vary from the exact form shown as iong as the construction produces concentration and a slit opening.

There are many uses for the present lamp, which will occur to those skilled in the art, but it is to be understood that the scope of the invention will be defined by the appended claims.

I claim:

1.111 a recording lamp, an envelope, a cathode of tungsten and an anode of Swedish iron within said envelope, said cathode and anode being heat treated to a steel blue color, and means for producing a glow between said cathode and anode,

said glow being evenly distributed over said cathode.

2. In a recording lamp, an envelope, a cathode of tungsten and an anode of Swedish iron within said envelope, a nickel support for said anode, and means for producing an evenly distributed glow over said cathode.

3. The method of producing a uniform flow of current between glow-producing electrodes including the step of annealing said electrodes to a steel-blue color.

4. The method of producing a uniform flow of current between glow-producing electrodes within an evacuated envelope including the step of annealing said electrodes to a steel-blue color while positioned within said envelope.

5. The method of producing a uniform flow of current between a tungsten cathode and a Swedish iron anode within an evacuated envelope and adapted to produce an illuminating glow therebetween including the step of annealing said tungsten and Swedish iron to a steel-blue color Within said envelope.

/ JOSEPH 2B. ZETKA. 

